But where did all the atoms in periodic table come from?
In the beginning the universe was full of hydrogen atoms.
The sun uses a series of nuclear reactions called the hydrogen cycle. In the heart of the sun protons fuse together to give a Helium nucleus. The first reaction in this sequence is very slow and explains why the sun is still shining after 5 billion years.
Homework: Put a heading in your book with the date.
The universe started off with only one element, hydrogen. Our sun burns the protons from hydrogen atoms and converts them to helium. Do a bit of research to find out how the remaining elements in the periodic table are formed. (hint: think about supernova) Write a brief account outlining how other elements are generated. The best three answers win a Mars bar.